When decoding video data, it is often necessary to obtain a video parameters such as bit rate, resolution, and the like. Without this information, it may not be possible to accurately decode the video data, and a user thus may be unable to view the video. Accordingly, it is also often necessary for an encoded video stream to include this information, which may be provided in a so-called key frame, that allows a viewer to decode the video. Often, an encoded video includes a single key frame at the start of the video.
Key frames or other messages including decoding information are significantly larger than other compressed video frames due to the amount and type of information they contain. In some prior art applications, key frames may be sent on a random or periodic basis. This results in frequent transmission of key frames or other similar information sets, which can lead to disadvantageous increases in bandwidth required to provide streaming video. Accordingly, to reduce the required bandwidth, some prior art applications may significantly limit the transmission of key frames or other decode information. For example, a key frame for a streaming video may be transmitted only once per period, with some periods being 20 seconds or more. As a result, new viewers may wait up to 20 seconds before the video data can be decoded and displayed. The delay in video display leads to a lower viewer quality experience and may lead a user to believe a connection is incorrectly established or that there is a software or hardware problem with the videoconferencing equipment.
These and other problems may be particularly acute in videoconferences, and particularly in large scale videoconferences where numerous users are sending audio and video data to one another in real time. Such conferences can require large bandwidth capacity and there may be a premium placed on reducing periodic key frame transmission to conserve the same. Viewer experience is often highly valued in such applications, however, with the result that delays in new user join time are troublesome.